Republicans, Democrats, and their advocacy groups are gearing up to navigate an Election Day governed by voting rules that have changed since the last national election – some of which are still tied up in the courts.

For Republicans, the effort is about maintaining ballot integrity and preventing fraud. Democrats and their allies, meanwhile, say the focus is on maximising participation.

No matter the ideology, the rules for voting are different in many states than they were in 2012. Here is a look at the varying landscape.

VOTER ID

The US Supreme Court has allowed a new photo identification requirement to stand in Texas, while lower courts consider a constitutional challenge to the law. But the high court blocked a similar requirement in Wisconsin, where Republican Governor Scott Walker, a potential 2016 White House contender, is seeking a second term.

The Arkansas Supreme Court struck down that state’s new photo ID requirement, so it won’t be in play as Republican Tom Cotton tries to knock off Democratic Mark Pryor, the incumbent.

In North Carolina, where Democratic Kay Hagan is in a fierce re-election battle with Republican Thom Tillis, some voters may think photo identification is required, but that provision of the state’s sweeping new voting law doesn’t take effect until 2016.

Democratic-controlled Illinois, meanwhile, enacted rules that apply only to this year’s governor’s race that scrapped a photo ID requirement for the state’s early voting period.

REGISTRATION

Iowa residents who have yet to register can still have a say between Republican Joni Ernst and Democrat Bruce Braley, another tight Senate match-up. Iowa is one of 10 states that allow voters to register and cast a ballot on the same day.

PROVISIONAL BALLOTS

Provisional ballots are required in every state under federal law approved after the 2000 presidential election. They allow a would-be voter to cast a ballot that is counted only if the citizen later proves he should be legally registered. States set different post-election deadlines – typically between three days and seven days – for the citizen to produce the required documentation.

EARLY OR ABSENTEE VOTING

At least 16.4 million people had already voted in 31 states as of last Saturday, according to data compiled by The Associated Press. Arkansas, Florida, Georgia, Iowa, Louisiana, Maryland, Montana, North Carolina, and Wisconsin surpassed their 2010 advance vote totals.

Thirty-three states allow some kind of early voting. Among those that don’t is Kentucky, where Senate Minority Leader Mitch McConnell faces Democrat Alison Lundergan Grimes.

MAIL-IN BALLOTS

In Colorado, where Republican Cory Gardner and Democratic Mark Udall are in a tight race, voters will vote almost entirely by mail for the first time. Colorado joins Washington and Oregon as states that mail ballots to every registered voter ahead of the election.